Introduction to musculoskeletal modelling

Abstract In this chapter, we introduce musculoskeletal modelling and how such models can be applied to estimate internal quantities that are difficult or impossible to measure experimentally such as muscle, joint, and ligament forces. We briefly introduce the different simulation approaches available before we go through an inverse dynamics approach in detail, describing how to perform kinematic and kinetic analysis and the underlying models of bones, joints, and muscles. For kinetic analysis, we cover the topic of muscle recruitment, which is required to handle the so-called underdeterminacy problem within the model. We also briefly introduce the Force-dependent Kinematics (FDK) simulation approach as an extension to inverse dynamics and describe how it enables advanced models of joints. After the theoretical framework has been established, we describe how cadaver-based template models are created and how they are made subject-specific depending on the available data. Finally, we introduce a few model applications to show the diverse possibilities these models offer.